Helix amplifier fittings

ABSTRACT

A helix amplifier pipe fitting may include an elbow or straight pipe fitting including an expanded helix portion, a plurality of helix vanes at an angle of incidence to the incoming fluid flow to impart rotational velocity on the fluid. A helix amplifier may include a helix discharge amplifier having a tapered canister, a tapered helix portion including a plurality of helix vanes, and a tapered mixing chamber.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit of the following U.S. Provisional PatentApplication Ser. No. 62/202,108 filed Aug. 6, 2015; Ser. No. 62/066,189filed Oct. 20, 2014; Ser. No. 62/089,968 filed Dec. 10, 2014; Ser. No.62/090,571 filed Dec. 11, 2014; and, Ser. No. 62/087,978 filed Dec. 5,2014. The disclosures of the preceding U.S. Provisional PatentApplications are hereby incorporated into this application.

BACKGROUND

Uneven erosion in piping systems, especially elbow fittings, leads topipe failure or early fitting replacement, either of which is costly inmaterial, manpower and downtime. Applications for transporting andpumping fluids and media comprising abrasive contents, such as coal andsand slurries, wet sand, gravel and similar contents, suffer especiallyhigh costs from uneven component wear.

When fluids/media pass through an elbow fitting, the change in directioncreates turbulent conditions, flow separation and vortex shedding alongthe pipe wall at the inside of the bend, and may create standing eddiescausing backflow conditions at points along the fitting pipe walls. Theconditions generally cause the elbow fitting pipe wall along the outsideof the bend to erode substantially faster than the pipe wall along theinside of the bend, as the fluid/media impinges directly against thewall along the outside of the bend as it enters the fitting and changesdirection. Additionally, heavier solids and particulates will be thrownto the outside wall as the fluid/media changes direction, so willcontinually scour the outer wall with new solid/particulate materials.In addition to high rates of localized wear on pipe walls, theturbulence and flow separation in the elbow fittings create head losswhich must be compensated for by higher pressure pumps, and can createsevere vibration and heating problems in the piping system.

Long radius elbow fittings and pipe sections can reduce these effects.However, long radius fittings require a great deal of space relative tostandard short radius fittings. Additionally, long radius fittings stillsuffer accelerated erosion rates along the pipe wall along the outsideof the bend because momentum still causes heavier particulate materialsto be thrown to the outer wall, and they are continually scoured by newparticulate/aggregate material.

A similar uneven erosion effect is experienced in long straight piperuns, as the concentration of particulates will increase in the lowerregion of the fluid in long straight runs, making the bottom portion ofthe fluid stream more abrasive the upper portion. Additionally, in largediameter piping systems, the weight of the fluid and media is born bythe lower pipe wall portion, causing higher erosion rates.

The inventors developed a new elbow fitting design which substantiallyeliminates uneven erosion within the fitting by inserting helix vanesalong the outside pipe wall, which rotates the fluid around the pipingcenterline axis through the bend of the fitting. In addition, the elbowcross section is expanded in the direction of the outside pipe wall,which traps a layer of particulates in the helix channels between thehelix vanes. During steady flow conditions, the fluid/media streamcontinuously erodes and redeposits this deposit layer rather thandirectly against the pipe wall. The rotation causes the fluid/mediastream to follow nearly equal path lengths through the elbow fitting,and forces flow along the inside pipe wall as well as the outside pipewall, with a more uniform velocity profile around the entire pipe wall,such that pipe wall erosion is distributed evenly around thecircumference of the pipe wall throughout the elbow fitting. Thebeneficial even pipe wear has been found to extend far downstream of ahelix elbow fitting as well.

The inventors discovered additional benefits, as well. Head loss througha helix elbow fitting was found to be substantially less thanconventional elbow fittings. The inventors believe this is due toseveral factors. The helix vanes and channels channelize the flowclosest to the pipe wall, thereby maintaining laminar flow conditions(or closer to laminar flow conditions) within the channels through theelbow fitting. The rotation causes all of the fluid streams to followsubstantially equal path lengths through the fitting, reducing oreliminating flow separation and eddy losses. Additionally, rotating thefluid streams around the pipe wall circumference creates a longereffective bend radius as the flow streams follow longer paths throughthe same bend angle. Finally, the clockwise rotation creates a resultingtorque vector, based on the Right Hand Rule, which aligns with thenominal pipe centerline, similar to a rifling effect.

The inventors found that the improved erosion profiles and head lossreduction extended far downstream, as well. The inventors thereforedeveloped helix straight fittings for installation in straight pipingruns as well. The rotation imparted on the fluid/media streamssubstantially eliminated localized bottom wall erosion downstream, andreduced head loss in the downstream piping runs. The expandedcross-section of the helix portion provided a similar sacrificialdeposit layer, reducing erosion along the fitting pipe walls.

For general applications, the inventors found that at least three helixvanes were necessary to impart sufficient rotation on the fluid/mediastream. However, the optimum number and spacing of the helix vanes isdependent on the anticipated fluid/media properties, including pressure,flow velocity, specific gravity, viscosity, temperature, particulateloading and size, incline, angle of change, and pipe material.Optimization can be performed using flow modeling software that iswidely available, as well as interpolating empirical data from installedsystems, which is within ordinary skill of persons in this field.

The inventors found that the downstream flow improvements from the helixstraight fittings could be used to improve discharge hose performance aswell, for example in firefighting situations, water blasting operations,irrigation applications, water cannons, and other applications requiringaccurate projection of a concentrated fluid stream over a distance.Installing a helix discharge amplifier immediately upstream of adischarge nozzle created a very concentrated discharge stream, due tothe rotation, with improved discharge velocity due to the reducingeffect and reduced head loss through the discharge nozzle. Additionally,the improved concentration provided by the stream rotation eliminatedthe need for flow straighteners upstream of the discharge nozzles,eliminating a major source of head loss.

An additional, unanticipated benefit was obtained from the helixdischarge amplifier. Newton's Third Law of Motion states that when onebody exerts a force on a second body, the second body simultaneouslyexerts a force equal in magnitude and opposite in direction on the firstbody. The result, for firefighters operating firehoses, is that the hoseoperators must exert a force equal to the force of the water exiting thehose nozzle in order to control the hose nozzle—i.e. the force of over ahundred gallons per minute of pressurized water, referred to as “backpressure” or “hose kick”. Normally, three firefighters are required tooperate a single 1.5-inch or 2.5-inch hose/nozzle due to the reactionforce, referred to as “hose kick” or “kickback”. The nozzleman holds anddirects the discharge nozzle itself. The backup nozzleman physicallysupports the nozzleman, assists in holding up the weight of the hose andnozzle, and provides relief when the nozzleman becomes fatigued. Thehoseman assists in moving the hose behind the nozzleman and backupnozzleman, to align it with the nozzle orientation so the nozzle iseasier to direct, and provides relief when the others become fatigued.However, installing a helix discharge amplifier immediately upstream ofthe nozzle virtually eliminated hose kick. In testing, the improvementwas so substantial that a single firefighter could operate the hosenozzle for extended periods, without backup, and even hold and directthe nozzle with one arm. The discharge stream was also much more focusedand accurate, and maintained this concentration and accuracy over alonger distance.

SUMMARY AND ADVANTAGES

A helix elbow fitting includes a plurality of helix vanes disposed alongthe interior pipe wall along the outside of the bend, the helix vanesbeing at an angle of incidence to the incoming fluid flow in order toimpart rotation on the fluid stream. A helix elbow fitting includes anexpanded cross-section in the region of the helix vanes, therebycreating a deposit layer in the helix channels and lengthening theeffective bend radius of the fluid stream through the elbow fitting. Thehelix elbow fitting includes and expander and reducer to transitionbetween the nominal system pipe diameter and the helix portion expandedcross-section. The helix vanes project into the fluid stream, preferablypast the outer boundary layer or at least 10 percent of the nominalsystem pipe diameter, or at least 10 percent of the major axis of thehelix portion expanded cross-section. Each helix vane extends from afirst end to a second end, but does not extend around the circumferenceof the elbow fitting pipe wall.

A helix straight fitting includes an expanded helix portion having across-section symmetrical and concentric to the nominal pipe systemcross-section, at least at the inlet, and a plurality of vanesdistributed equidistantly around the circumference of the helix portioncross-section. The helix straight fitting includes and expander andreducer to transition between the nominal system pipe diameter and thehelix portion expanded cross-section. Each of the helix vanes isoriented at an angle of incidence to the incoming flow, and extendslongitudinally through the length of the helix portion. The helixportion expanded cross-section tapers from the helix inlet to the helixoutlet. The helix vanes project into the fluid stream similarly to helixelbow fitting helix vanes.

A helix discharge amplifier is similar to a helix straight fitting, butincludes a straight and continuous taper from the helix portion expandedcross-section inlet to the amplifier outlet, without a reducer, and theamplifier outlet is couplable to a nozzle or other discharge fitting.The helix portion includes a plurality of helix vanes distributedequidistantly around the helix portion cross-section, oriented at anangle of incidence to the incoming fluid stream, and extending thelength of the helix portion. A tapered mixing chamber extends from thehelix portion outlet to the amplifier outlet.

The helix fittings of the present invention provide many advantages,including: (1) reduced localized pipe wall erosion; (2) reduced systemhead loss; (3) reduced vibration through pipe bends; (4) improveddischarge flow characteristics; and, (5) reduced hose kick for dischargeapplications.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated into and constitute apart of this specification, illustrate one or more embodiments of thepresent invention and, together with the detailed description, serve toexplain the principles and implementations of the invention.

FIG. 1 shows a perspective view of a First Embodiment.

FIG. 2 shows a side view of a First Embodiment.

FIG. 3 shows a side view of a First Embodiment.

FIG. 4 shows an interior view of the helix portion of a Firstembodiment, from the inlet.

FIG. 5 shows an end-on cutaway view of a First Embodiment, cut throughthe helix portion.

FIG. 6 shows a cutaway view of a First Embodiment, cut front-to-back.

FIG. 7 shows a cutaway view of a First Embodiment, cut along first andsecond longitudinal transition lines.

FIG. 8 shows a quarter-cutaway view of the helix portion of a FirstEmbodiment.

FIG. 9 shows a velocity/pressure profile of a First Embodiment inoperation, from a side view.

FIG. 10 shows another velocity/pressure profile of a First Embodiment inoperation, from a side view.

FIG. 11a shows an expanded helix portion cross-section of a FirstEmbodiment.

FIG. 11b shows an alternative expanded helix portion cross-section of aFirst Embodiment, having an oval cross-section.

FIG. 12 shows a side view of a Second Embodiment.

FIG. 13 shows an interior perspective view of a Second Embodiment.

FIG. 14 shows a perspective view of the interior of a Second Embodiment,from the inlet end.

FIG. 15 shows a partially transparent side view of a Second Embodiment.

FIG. 16 shows a cutaway side view of a Second Embodiment.

FIG. 17 shows a cutaway side perspective view of a Second Embodiment.

FIG. 18 shows a velocity profile of a Second Embodiment in operation.

FIG. 19 shows a partially exploded perspective view of a ThirdEmbodiment.

FIG. 20 shows an exploded perspective view of a Third Embodiment.

FIG. 21 shows a cutaway side view of an assembled Third Embodiment.

FIG. 22 shows a partial cutaway side view of an assembled ThirdEmbodiment.

FIG. 23 shows a perspective view of a helix insert of a ThirdEmbodiment.

FIG. 24 shows a partial cutaway perspective view of a helix insert of aThird Embodiment.

FIG. 25 shows a cutaway discharge-end perspective view of a helix insertof a Third Embodiment.

FIG. 26 shows a cutaway inlet-end perspective view of a helix insert ofa Third Embodiment.

FIG. 27 shows a side view of a Fourth Embodiment.

FIG. 28 shows the helix portion of a Fourth Embodiment.

FIG. 29 shows the front side portion of a Fourth Embodiment.

REFERENCE NUMBERS USED IN DRAWINGS

Turning now descriptively to the drawings, in which similar referencecharacters denote similar elements throughout the several views, thefigures illustrate several embodiments of the present invention. Withregard to the reference numerals used, the following numbering is usedthroughout the various drawing figures:

-   -   10 First Embodiment Helix Elbow Fitting    -   12 Helix Elbow Fitting Inlet Portion    -   14 Helix Elbow Fitting Outlet Portion    -   16 Helix Portion    -   18 Inlet Coupling    -   20 Outlet Coupling    -   22 Expander    -   24 Helix Portion Inlet    -   26 Helix Portion Outlet    -   28 Helix Portion Expanded Cross-Section Area    -   30 Reducer    -   32 Helix Vanes    -   34 Helix Vane First Ends    -   36 Helix Vane Second Ends    -   38 Helix Channels    -   40 First Longitudinal Transition Line    -   42 Second Longitudinal Transition Line    -   44 Rotation/Torque Vector Diagram    -   46 Helix Vane Depth    -   48 Helix Vane Cross Section Area    -   50 Helix Vane Angle of Incidence    -   52 Helix Expanded Cross-Section Front Portion    -   54 Helix Expanded Cross-Section Back Portion    -   56 Helix Vane Angle of Attack    -   58 Helix Elbow Fitting Front Side Pipe Wall    -   60 Helix Portion Interior Wall    -   110 Second Embodiment, Helix Straight Pipe Fitting    -   112 Helix Straight Pipe Fitting Inlet Portion    -   114 Helix Straight Pipe Fitting Outlet Portion    -   116 Helix Portion    -   118 Inlet Coupling    -   120 Outlet Coupling    -   122 Expander    -   124 Helix Portion Inlet    -   126 Helix Portion Outlet    -   128 Helix Portion First Expanded Cross-Section    -   130 Reducer    -   132 Helix Vanes    -   134 Helix Vane First Ends    -   136 Helix Vane Second Ends    -   138 Helix Channels    -   140 Not used    -   142 Not used    -   144 Rotation/Torque Vector Diagram    -   146 Helix Vane Depth    -   148 Helix Vane Cross Section Area    -   150 Helix Vane Angle of Incidence    -   152 Not used    -   154 Not used    -   156 Helix Vane Angle of Attack    -   158 Not used    -   160 Helix Portion Interior Wall    -   162 Helix Portion Second Expanded Cross-Section    -   164 Helix Portion Tapered Centerline Channel    -   210 Third Embodiment, Helix Discharge Amplifier    -   212 Helix Discharge Amplifier End Cap    -   214 Helix Discharge Amplifier Outlet Portion/Canister Outlet End    -   216 Helix Portion    -   218 End Cap Inlet Coupling    -   220 Amplifier Discharge Coupling    -   222 Not used    -   224 Helix Portion Inlet    -   226 Helix Portion Outlet    -   228 Helix Portion Inlet Cross-Section    -   230 Discharge Mixing Chamber    -   232 a-c Helix Vanes    -   234 a-c Helix Vane First Ends    -   236 a-c Helix Vane Second Ends    -   238 a-c Helix Channels    -   240 Not used    -   242 Not used    -   244 Rotation/Torque Vector Diagram    -   246 Helix Vane Depth    -   248 Helix Vane Cross Section Area    -   250 Helix Vane Angle of Incidence    -   252 Not used    -   254 Not used    -   256 Helix Vane Angle of Attack    -   258 Not used    -   260 Helix Portion Interior Wall    -   262 Helix Portion Second Cross-Section    -   264 Helix Portion Tapered Centerline Channel    -   266 Canister    -   268 Canister Tapered Interior Wall    -   270 Canister Inlet End    -   272 Canister Inlet End Diameter    -   274 Canister Outlet End Diameter    -   276 Canister First End Threaded Coupling    -   278 a-c Helix Vane Edge    -   280 a-c Helix Vane Inlet Corner    -   282 a-c Helix Vane Outlet Corner    -   284 Discharge Mixing Chamber Length    -   286 Helix Portion Taper Angle    -   310 Fourth Embodiment, Two-Piece Helix Elbow Fitting    -   310 a Helix Elbow Front Portion    -   310 b Helix Elbow Back (Helix) Portion    -   316 Helix Elbow Helix Portion    -   386 Helix Elbow First Flange    -   388 Helix Elbow Second Flange

DETAILED DESCRIPTION

Before beginning a detailed description of the subject invention,mention of the following is in order. When appropriate, like referencematerials and characters are used to designate identical, corresponding,or similar components in differing figure drawings. The figure drawingsassociated with this disclosure typically are not drawn with dimensionalaccuracy to scale, i.e., such drawings have been drafted with a focus onclarity of viewing and understanding rather than dimensional accuracy.

In the interest of clarity, not all of the routine features of theimplementations described herein are shown and described. It will, ofcourse, be appreciated that in the development of any such actualimplementation, numerous implementation-specific decisions must be madein order to achieve the developer's specific goals, such as compliancewith application- and business-related constraints, and that thesespecific goals will vary from one implementation to another and from onedeveloper to another. Moreover, it will be appreciated that such adevelopment effort might be complex and time-consuming, but wouldnevertheless be a routine undertaking of engineering for those ofordinary skill in the art having the benefit of this disclosure.

In this Specification, references to the “diameter” of a pipe or fittingrefer to the inner wall diameter, unless stated otherwise. Similarly,references to the “cross section” of a pipe or fitting refer to theplanar area bounded by the interior walls of the pipe or fitting.References to a “nominal pipe” or “nominal fitting” refer to thedimensions or cross-section of the system smooth-interior-walled pipingor standard smooth-interior-walled fittings for such piping.

“Elbow” fittings refers to pipe fittings used to change the direction offlow of the piping system, and include any bend angle, not simply90-degrees. Although the described embodiments are sized to swap outwith standardized pipe fittings, the helix elbow fitting is not limitedby bend radius or length, which will vary widely depending on the pipingsystem itself.

In the Description, reference may be made to the “front” and “back” of ahelix elbow fitting. This refers to the portion of pipe closest to theinside of the bend radius (“front portion”) and the portion along theoutside of the bend radius of the fitting (“back portion”),respectively, but do not imply that the helix elbow fitting is only usedin a horizontal plane.

Referring to FIGS. 1-10 and 11 a&b, a First Embodiment is showncomprising a helix elbow fitting 10 with a ninety-degree (90°) bend.Fitting 10 includes inlet portion 12, outlet portion 14, and helixportion 16 extending from helix portion inlet 24 to helix portion outlet26. Inlet and outlet portions 12 and 14 include inlet and outletcouplings 18 and 20, respectively, which are adapted to tie into theselected piping system based on user needs. Couplings 18 and 20 may useany coupling mechanism compatible with the piping materials andoperating conditions. In the embodiment, coupling portions 18 and 20 aresimply pipe stub couplings for welding to a nominal pipe.

Helix portion 16 includes a plurality of helix vanes 32 to impartrotational motion to the fluid/media. Helix vanes 32 definecorresponding helix channels 38. The inventors have determined that, forgeneral slurry applications, at least three helix vanes 32 are necessaryto impart sufficient rotation on the fluid/media to achieve a usefulevening of pipe wall wear along the front and back inner walls of anelbow, and to also achieve reduced head loss through the elbow. However,the optimum number of helix vanes 32 and corresponding helix channels 38depends on the anticipated range of operating conditions, such aspressure, flow velocity, temperature, viscosity, particulate size,specific gravity, and importantly, the nominal pipe diameter, elbow bendangle and bend radius. For example, a 90-degree helix pipe elbow for a3-inch diameter piping system for a high-specific gravity applicationsuch as foundry sand might have six helix vanes 32 spaced over a6.75-inch long (170 mm) helix portion, whereas a 90-degree helix pipeelbow for a 72-inch (1.8 m) diameter piping system for a slurry mixmight incorporate three-hundred or more helix vanes spaced over a15-foot long (4.6 m) helix portion.

Helix portion 16 has a cross section 28 which is greater than the crosssection A of the system piping interior, expanding out toward the backside portion of helix pipe fitting 10. Helix portion cross section 28comprises a stadium or oval shape, with the front portion 52 of thestadium or oval matching the nominal pipe diameter and the back portion54 expanding outward to contain helix vanes 32. In the embodiment, helixportion cross section 28 comprises a stadium with opposed front and backsemicircles, 52 and 54 respectively, equivalent to one-half of thenominal pipe interior cross-section. The opposed joints of the frontsemicircle 52 and rectangular section of the stadium cross-section 28define opposed first and second longitudinal transition lines 40 and 42,respectively, of helix portion 16. First and second longitudinaltransition lines 40 and 42 are separated by approximately 180-degreesaround the front half-circle 52. In cases where helix portion crosssection 28 comprises an oval shape, first and second longitudinal axis40 and 42 would be separated by less than 180-degrees (e.g. see FIGS.11a and 11b , 40′ and 42′).

The expanded cross-section 28 serves two functions. First, the expandedcross section compensates for the cross sectional area of helix vanes 32in order to maintain the effective cross-section of helix portion 16approximately equal to or greater than the cross section A of thenominal piping system. Helix portion cross section 28 is equal to thesum of A (cross section of the nominal piping system)+n (48) (the totalcross sectional areas of helix vanes 32). In the case of an embodimenthaving helix vanes with cross sections varying along the length of thevane, then the effective cross section of the vanes would be used.

The second function of the expanded cross-section 28, for slurry, wetsand and other high aggregate fluids/media, is to create a deposit zone,where particulates and aggregate continuously are deposited in helixchannels 38 and carried out, such that the primary erosion processoccurs against these deposits within helix channels 38, rather than thebackside pipe wall, thereby extending the life of the helix elbowfitting 10.

Helix vanes 32 extend beyond the nominal inner pipe wall to a helix vanedepth 46, slightly past the fluid boundary layer and into the laminarflow portion of the fluid stream. The inventors found that if helixvanes 32 do not extend far enough into the fluid/media, then the helixvanes 32 will create substantial turbulence-induced head loss, hightemperatures and vibration, without imparting sufficient rotation to thefluid/media to substantially reduce the head loss compared to thenominal equivalent pipe fitting (e.g. a standard elbow). If helix vanes32 extend too far, then again the losses from increased friction andinduced drag exceeds the gain over a nominal equivalent pipe fitting.Ideally, in a piping system designed to carry a fluid/media havingconsistent operating conditions the “ideal” helix vane depth 46 would bedetermined by empirical or predictive modeling methods, because theboundary layer for a given fluid/media will depend on the conditions. Inreality, actual operating conditions will vary greatly. Fluid/mediawhich include large proportions of solids and/or aggregates, and drysolids media such as sand and gravel, may not have a well-definedboundary layer. The inventors have determined, by modelling andexperimentation under varying conditions representing fieldapplications, that a penetration depth of at least ten percent (10%) ofthe nominal pipe diameter for symmetric helix fittings, or ten percent(10%) of the major axis diameter for asymmetric helix fittings, areeffective to reduce head loss over a broad range of operatingconditions.

Inlet portion 12 further includes expander 22, extending from inletcoupling 18 to helix portion inlet 24. Expander 22 transitions fromsystem pipe cross-section A to helix portion cross section 28. Outletportion 14 further includes reducer 30, extending from helix portionoutlet 26 to outlet coupling 20. Reducer 30 transitions from helixportion cross section 28 to system pipe cross-section A, or whatever theimmediate downstream system component may be. For example, thedownstream nominal pipe diameter might be smaller than the upstreamnominal pipe diameter

Each of helix vanes 32 extend from a first end 34 disposed along firstlongitudinal transition line 40 to a second end 36 n disposed alongsecond longitudinal transition line 42, with first and secondlongitudinal transition lines 40 and 42 separated approximately180-degrees around the helix expanded cross-section front portion 52.

Helix portion 16 extends around at least a portion of the bend angle ofhelix elbow fitting 10. In the embodiment, elbow fitting 10 has a90-degree bend angle, and helix portion 16 extends along approximately45-degrees of the bend angle.

Each of helix vanes 32 is oriented at an angle of incidence 50 to thenominal pipe system fluid/media flow direction. In the embodiment, theangle of incidence 50 is approximately 30-degrees. The inventors havedetermined that the optimum angle of incidence 50 is between 15-degreesand 45-degrees for typical sand-slurry applications, depending on theanticipated operating parameters. For typical sand-slurry applications,an angle of incidence 50 of less than 15-degrees would not impartsufficient rotation within the span of a typical fitting length toprovide substantial net reduction in head loss or even out wear. Anangle of incidence 50 of greater than 45-degrees tends to createexcessive head loss to induced drag, and leads to “tumble over” effectunless flow velocity is maintained unusually low. “Tumble over effect”refers to the tendency of the fluid/media to simply flow over helixvanes 32—like tumbling over the top of a dam—rather than flowing throughhelix channels 38 to impart rotation to the fluid/media. “Tumble over”also leads to excessive head loss and high temperatures and vibration.Alternatively, helix vanes 32 could incorporate a variable angle ofincidence 50, for example initially 15-degrees and increasing to somemaximum, for example 45-degrees. Helix vanes 32 have an angle ofincidence 50 to impart a clockwise vorticity, such that the resultingtorque vector (exemplified by vector diagram 44) aligns with the nominalpipe system fluid flow direction in accordance with the “Right HandRule”. For very high density/high particulate media, for examplewet-sand and foundry-sand mixes, the optimal angle of incidence 50 mayextend to as little as 5-degrees to 15-degrees.

In the embodiment, the angle of attack 56 of helix vanes 32 is ninetydegrees, as helix vanes 32 project radially inward, normal to theincoming fluid direction of flow. For slurry and other heavyparticulate, heavy aggregate, high specific gravity or high viscosityfluids/media a ninety-degree angle of attack is generally preferable, toprevent material from becoming packed into helix channels 38, ratherthan loosely deposited. Additionally, a ninety-degree angle of attack iseasier to manufacture. However, for applications without suchlimitations, an angle of attack of less than ninety-degrees may beoptimal.

The described helix elbow fitting 10 is effective for bend angles ofapproximately 10-degrees to approximately 175-degrees. For bend anglesof less than 10-degrees, a straight helix reducer (as described in theSecond Embodiment) installed immediately upstream of a nominal bendfitting would likely be more effective. For bends greater than175-degrees, a series of smaller helix elbow fittings would likely bemore efficient (for example, 90-degree helix elbow in series with asecond 90-degree helix elbow, separated by a short nominal pipe section,to provide a 180-degree bend). A helix elbow fitting 10 could form partof a sweeping continuous curved bend, including sweeping curves equal toor greater than 180-degrees. However, use of helix elbow fittingsprovide similar head loss reductions and avoid localized erosion, socould achieve similar results in a more compact piping system layout.

In operation, fluid/media entering helix elbow fitting 10 distributesthrough expander 22 and enters helix portion 16. Fluid/media flowingalong the nominal piping system back pipe wall impinges against helixvanes 32, causing it to alter its flow path and velocity profile tofollow helix channels 38 in a clockwise rotation. This in turn impartsrotation onto at least the outer layers of the fluid/media stream, withthe greatest angular velocity in the fluid/media proximate the helixelbow fitting pipe wall and lower angular velocity along the nominalpiping centerline. The angular velocity of the rotating stream, and theasymmetric cross-section 28 of helix portion 16, causes particulates oraggregate (if present) to move toward the pipe wall and create a depositlayer in helix channels 38 within helix portion 16. Under steady-stateconditions, fluid/media flowing through helix channels 38 willcontinuously deposit and entrain particulates or aggregate, achieving anequilibrium condition, such that the primary erosion effect is againstthis sacrificial layer, rather than the backside pipe wall.

Referring to FIGS. 9 and 10, velocity profiles of fluid passing througha helix elbow fitting 10 are shown. The rotation of fluid/media throughthe bend of helix elbow fitting 10 causes the fluid/media to contact theentire circumference of the helix elbow fitting pipe wall, atsubstantially consistent velocity and angle, such that the pipe wallerodes evenly around its entire circumference, rather thanpreferentially in a single area, which extends the life of the fitting.FIGS. 9 and 10 demonstrate that the fluid velocities at the front sidewall and back side wall are substantially equal, and that the fluid isaccelerated toward the helix outlet.

Additionally, helix channels 38 create a channeling effect, whichmaintains substantially consistent laminar flow conditions within helixchannels 38 and continuing around the circumference of helix pipefitting 10, rather than allowing the flow along the front side pipe wall58 of the helix elbow fitting to separate from the pipe wall, creatingexcessive head loss, vibration and pipe wall damage due to vortexshedding and eddies. In addition to the channeling effect, helixchannels 38 cause the fluid/media to follow longer—and substantiallyequal—flow paths rather than simply “turning the corner”, therebyeffectively creating a longer bend radius and lower flow losses. Waterhammer caused by air pocket formation and collapse is largelyeliminated, as the laminar flow channeling and reduced turbulence tendto prevent low-pressure/dead-space pockets between opposed vorticeswhere gas pockets may accumulate. Also, the rotation imparts verticalflow vectors, so gas pockets are more easily swept away via helixchannels 38.

Helix Straight Pipe Fitting

Referring to FIGS. 12-18, a Second Embodiment is shown, comprising ahelix straight pipe fitting 110. The helix straight pipe fitting 110includes inlet portion 112, outlet portion 114 and helix portion 116.Inlet and outlet couplings 118 and 120, respectively, are provided ateither end for coupling into the nominal pipe system. Expander 122extends from inlet coupling 118 to helix portion inlet 124. Reducer 130extends from helix portion outlet 126 to outlet coupling 118.

In the embodiment, helix portion 116 has a first expanded cross section128 at helix portion inlet 124 and tapers to a second expanded crosssection 162 along helix portion interior wall 160. In the embodiment,helix portion 116 has symmetrical cross section from first expandedcross-section 128 to second expanded cross-section 162, which isconcentric with the nominal system piping. The area of first expandedcross section 128 is at least as large as the nominal inlet pipe crosssection A plus the cross sectional area 148 of the helix vanes 132, tomaintain approximately the same effective cross-sectional area as thenominal inlet pipe. In the embodiment, the depth 146 of helix vanes 132is constant, such that the effective flow area reduces along the lengthof tapered helix portion 116, creating a reducer effect whichaccelerates flow velocity such that the flow velocity at helix portionoutlet 126 is greater than at helix portion inlet 124.

In the embodiment, five helix vanes 132 are provided, spacedequidistantly around the circumference of helix portion interior wall160. Helix vanes 132 have an angle of incidence 150 to the incomingfluid/media flow so as to achieve a pitch of 1.0, in other words eachhelix vane 132 circumscribes the interior circumference of helix portion116 once. In the embodiment, each helix vane 132 has an angle of attack156 of ninety degrees. Helix vanes 132 do not contact each other, so asto leave an unobstructed tapered centerline channel 164 through helixportion 116.

In the embodiment, the helix straight pipe fitting inlet portion andoutlet portion are adapted for the same nominal pipe diameter, but theoutlet portion could be configured for a different nominal pipe size, orto couple to a different downstream system component or fitting.

Discharge Flow Amplifier

Referring to FIGS. 19-26, a Third Embodiment is shown comprising a helixdischarge flow amplifier 210. Helix discharge flow amplifier 210includes a canister 266, a helix portion 216 disposed within canister266, a canister end cap 212 provided at the inlet portion which includesan inlet coupling 218, a discharge mixing chamber 230, and dischargecoupling 220.

The Third Embodiment is optimized for a 2.5-inch standard firehose andnozzle combination for use with water and water-foam mix. Canister 266includes and interior wall 268 tapered from a canister inlet end 270having an inlet diameter 272 to a canister outlet end 214 having anoutlet diameter 274. Canister first end threaded coupling 276 isdisposed proximate canister inlet end 270 to sealingly engage end cap212.

Helix portion 216 extends from a helix portion inlet 224 to helixportion outlet 226. Helix portion 216 includes first, second and thirdhelix vanes 232 a-c, each projecting inward from helix portion interiorwall 260 to a respective helix vane edge 278 a-c, and each extendinglongitudinally from a respective first helix vane end 234 a-c proximatehelix portion inlet 224 to a respective second helix vane end 236 a-cproximate helix portion outlet 226. Helix vanes 232 a-c are distributedequidistantly at 120-degree intervals around the interior wall 260 ofhelix portion 216, and each of helix vanes 232 a-c has an angle ofincidence 250 to the fluid flow direction. In the embodiment, the angleof incidence is such that each helix vane 232 a-c circumscribesapproximately 180-degrees of the interior wall 260 of helix portion 216,or a 0.5 pitch. In the embodiment, helix vanes 232 a-c are oriented atan angle of attack 256 of less than ninety degrees, such that they donot project radially from the interior wall 260 of helix portion 216,thereby reducing flow separation losses, and with helix vane edges 278a-c defining a central tapered longitudinal open channel 264. In theembodiment, three helix vanes 232 a-c are provided, which providessubstantial head loss reduction, balanced rotation for improved nozzlehandling, concentrated discharge pattern, and reasonable manufacturingcosts using conventional manufacturing methods. However, optimizationfor specific fluid/media for operation under knownpressure/viscosity/flow conditions, and without manufacturing costrestrictions, may utilize more than three helix vanes 232, and mayutilize a greater or lesser angle of incidence 250 and/or angle ofattack 256.

In the embodiment, each of helix vane inlet corners 280 a-c,respectively, and helix vane outlet corners 282 a-c, respectively, areradiused in the plane of the respective helix vane. In the embodiment,the helix vane corners 280 a-c and 282 a-c have approximately a 1.0-inch(25.4 mm) radius. The inventors found that when the helix dischargeamplifier of the embodiment was used with aqueous film forming foam(“AFFF”, commonly used for fighting petroleum and certain chemicalfires) sharp helix vane corners 280 a-c and 282 a-c caused the AFFFfoam-water-mixture to expand within helix flow amplifier 210. Thisexpansion created severe loss of flowrate due to the two-phase flow. Theinventors found that providing radiused helix vane corners 280 a-c and282 a-c substantially eliminated this problem. For applications wherethe helix flow amplifier 210 would not be used with foaming agents, e.g.water-blasting or irrigation applications, the radiused helix vanecorners may not provide substantial advantage.

The tapered interior wall 268 of canister 266 extends past helix portionoutlet 226 to canister outlet end 214 (which also forms the helixdischarge amplifier outlet portion) defining discharge mixing chamber230. In the embodiment, the length 284 of mixing chamber is equal to orgreater than helix portion inlet diameter 228. In the embodiment,designed for a standard 2.5-inch firehose and nozzle operating at asupply system pressure of 30-250 psig, the helix portion inlet diameteris approximately 3.7 inches (94 mm) and mixing chamber length 284 isapproximately 4 inches (102 mm).

For standard firehose/water cannon applications, where supply pressureand flow conditions can vary substantially but the hose and nozzles tendto be standard or comprise a limited set of configurations, theinventors have determined that a helix portion taper 286 in the range of2-degrees to 10-degrees provides good flow amplification and relativecompactness. In the embodiment, for a 2.5-inch firehose, the helixportion taper 286 is 2.27°. In modelling and testing an embodiment for a1.5-inch standard firehose operating in the range 30-200 psig, theinventors determined that a helix portion taper of 3° provided a goodbalance of flow amplification and relative compactness. In modelling andtesting an embodiment for a 5.5-inch water cannon operating in the range70-350 psig, the inventors determined that a helix portion taper of 8°provided an optimal balance of flow amplification and relativecompactness.

In the embodiment, helix portion 216 is a removable insert, having ataper angle 286 which matches the taper of canister tapered interiorwall 268. End cap 212 holds helix portion insert 216 in place, andduring operation the water pressure naturally presses helix portioninsert 216 tightly against canister tapered interior wall 268, therebypreventing helix portion insert 216 from spinning during operation. Amechanical locking mechanism could also be provided for backup, such asa slot-and-key engagement or other mechanism. Helix portion insert 216is made from a polymer selected to have thermal andexpansion/contraction characteristics which are similar to the materialused for canister 266 within the anticipated temperature operatingrange, so as to remain firmly engaged against the tapered interior wall268 of canister 266, even when fluid and environmental temperaturesvary.

Providing a removable helix portion 216 has additional advantages. Thehelix portion 216 is a complex shape which would be expensive tomanufacture in metal, which is the typical material used forfirefighting hose fittings (brass and/or aluminum), but less expensiveto manufacture using plastics. Additionally, the helix portion 216 issubject to wear, and damage. Providing a lightweight, less expensive andmore readily replaceable insert reduces lifecycle costs and permitsrapid replacement repair under field conditions.

Discharge coupling 220 is connected to canister outlet end 214, toprovide a coupling for a discharge nozzle. In the embodiment, dischargecoupling 220 is a threaded fitting to couple to a typical 2.5-inchfirefighting hose nozzle.

In operation of the Third Embodiment, helix portion insert 216 isinserted into canister 266 until it is fully engaged against the taperedinterior wall 268 of canister 266. End cap 212 is threaded onto canisterfirst end threaded coupling 276. A 2.5-inch firehose is threaded to endcap inlet coupling 218, a 2.5-inch firehose nozzle is threaded toamplifier discharge coupling 220, and the firehose is pressurized. Whenthe firehose nozzle is opened to allow flow, the helix portion vanes 232a-c impart rotation to the water stream, and cause the flow to separateinto three separate rotating flow streams, converting much of the linearmomentum of the water stream into angular momentum, exemplified byvector diagram 244. Looking out through discharge 214, the rotation isclockwise, such that application of the Right Hand Rule results in atorque vector aligned with the direction of the discharge flow. Thethree separated rotating flow streams recombine into a single rotatingflow stream when they pass through discharge mixing chamber 230, andmaintain this unified rotating stream through canister/amplifier outlet214 and the firehose nozzle.

The result is that the discharge flow out of the firehose nozzle is muchmore concentrated than a non-rotated stream, and maintains thisconcentration for a much greater distance. Additionally, the head lossesare reduced, both due to the rotation and the fact that no flowstraightener is required upstream of the firehose nozzle as inconventional non-rotated systems. The reduced head losses provide forgreater flow volume over the pressure range. The operator may adjustsupply pump pressure as well, to further optimize operation with aparticular hose-nozzle configuration.

Importantly, the angular momentum and resulting torque vector 244substantially reduce the backward force felt by the nozzle operatorduring operation. Application of Newton's Third Law of Momentum meansthat, for a purely linear flow system, the nozzle operator must apply anequal and opposite force to overcome the momentum of over 100 gpm ofwater exiting the hose nozzle at high pressure. Typically, a team ofthree operators is required to safely handle a standard 1.5-inch (38 mm)or 2.5-inch (64 mm) firehose: a nozzleman, a backup nozzleman to supportthe nozzleman and provide a relief when the nozzleman gets fatigued, anda hoseman to move the firehose into alignment with the nozzleman.However, with the discharge amplifier 210 coupled between the hose andthe nozzle, a single operator can handle the firehose and nozzle,without assistance, even at full pressure and flow. In operation,trained firefighters using a discharge flow amplifier 210 could operatea 2.5-inch (64 mm) firehose nozzle at full flow using only one arm.

Although the described Third Embodiment is configured for use with afirehose and nozzle, a discharge flow amplifier 210 is useful for manyapplications requiring a concentrated water stream discharge, such aswater-blasters used for mining/sluicing, irrigation sprinklers,decorative fountains, water cannon for riot control, and other uses.

Referring to FIGS. 27-29 a Fourth Embodiment is shown. In the fourthembodiment of a helix elbow fitting 310, an alternative method ofconstruction is demonstrated whereby the helix elbow fitting 310 ismanufactured in first and second parts 310 a and 310 b, which can becoupled together, either by bolting the corresponding mating flanges 386and 388, or by welding. In the embodiment, first part 310 a isessentially the front part of a standard elbow fitting for the nominalpiping system diameter, and second part 310 b includes the expandedhelix portion 316. Second part 310 b could also be welded to an existingelbow fitting after cutting out its back side portion. In operation theembodiment works the same as the helix elbow fitting described in theFirst Embodiment 10.

Those skilled in the art will recognize that numerous modifications andchanges may be made to the preferred embodiment without departing fromthe scope of the claimed invention. It will, of course, be understoodthat modifications of the invention, in its various aspects, will beapparent to those skilled in the art, some being apparent only afterstudy, others being matters of routine mechanical, chemical andelectronic design. No single feature, function or property of thepreferred embodiment is essential. Other embodiments are possible, theirspecific designs depending upon the particular application. As such, thescope of the invention should not be limited by the particularembodiments herein described but should be defined only by the appendedclaims and equivalents thereof.

We claim:
 1. A helix elbow pipe fitting for a piping system having anominal pipe interior diameter, the helix elbow fitting having aselected bend angle and selected bend radius, the interior of the bendangle defining a front-side and the outside of the bend angle defining aback-side, the helix elbow pipe fitting comprising: an inlet, includingan inlet connection portion, and an opposed outlet, including an outletconnection portion; a helix portion extending from a helix portion inletto a helix portion outlet, the helix portion extending around at least aportion of the bend angle, the helix portion having an expandedcross-section relative to the nominal pipe cross-section, the expandedcross-section offset toward the helix elbow fitting back side and thedistance from the expanded cross-section back wall to the pipe fittingfront wall defining the major axis, the helix portion further includinga plurality of helix vanes distributed along and extending out from theback side wall of the helix portion expanded cross-section, each of thehelix vanes extending from a helix vane first end to a helix vane secondend and oriented at an angle of incidence to the incoming fluid ormedia, wherein the helix vane first end is upstream of the helix vanesecond end; an expander extending from the inlet connection portion tothe helix portion inlet; and, a reducer extending from the helix portionoutlet to the outlet connection portion; wherein, the helix portionimparts rotation on a bulk fluid, slurry or granular system flowingthrough it to laminar desired flow characteristics.
 2. An apparatus asin claim 1, further comprising: wherein the helix vanes extend past thenominal interior pipe wall diameter.
 3. An apparatus as in claim 2,further comprising: wherein the piping system is designed for ananticipated range of nominal fluid flow conditions in the piping system,the nominal fluid flow conditions including an anticipated range ofouter laminar boundary layer thickness in the fluid flowing through thepiping system proximate the nominal pipe wall; and, wherein, the helixvanes extend into the fluid flow at least as far as the maximum of theanticipated range of the outer laminar boundary layer of the flowingfluid.
 4. An apparatus as in claim 2, further comprising: wherein thehelix vanes extend past the nominal interior pipe wall diameter by at 10percent of the nominal interior pipe diameter.
 5. An apparatus as inclaim 2, further comprising: wherein the helix vanes extend past thenominal interior pipe wall diameter by at 10 percent of the major axisof the expanded cross section.
 6. An apparatus as in claim 1, furthercomprising: wherein the helix portion expanded cross-section comprisesan oval having a short radius defined by the nominal pipe front sideinner wall radius and a long radius defined by the radius of theexpanded cross-section back side interior pipe wall, the opposed jointsof the small and large radii defining opposed first and secondlongitudinal transition lines of the helix portion.
 7. An apparatus asin claim 1, further comprising: wherein the helix portion expandedcross-section comprises a stadium having a front side semicircle andopposed back side semicircle, each semicircle of the stadium equivalentto one-half of the nominal pipe interior cross section, and the opposedjoints of the front side semicircle and rectangular section of thestadium define opposed first and second longitudinal transition lines ofthe helix portion.
 8. An apparatus as in claim 6, further comprising:wherein the first and second ends of the helix vanes do not extend pastthe respective first and second longitudinal transition lines.
 9. Anapparatus as in claim 7, further comprising: wherein the first andsecond ends of the helix vanes do not extend past the respective firstand second longitudinal transition lines.
 10. An apparatus as in claims8 or 9, further comprising: wherein the helix vanes terminate flush withthe helix portion interior pipe wall at the helix vane second ends. 11.An apparatus as in claim 7, further comprising: wherein the plurality ofhelix vanes includes at least three helix vanes.
 12. An apparatus as inclaim 1, further comprising wherein the area of the helix portionexpanded cross-section is equal to or greater than the total of thenominal pipe cross-sectional area cross-sectional areas of the helixvanes.
 13. An apparatus as in claim 1, further comprising: wherein thelength of the helix portion is at least 2.25 times the nominal pipeinner diameter.
 14. An apparatus as in claim 1, further comprisingwherein the helix vane angle of incidence is within the range 5 degreesto 45 degrees.
 15. An apparatus as in claim 1, further comprisingwherein the helix vane angle of incidence is within the range 5 degreesto 15 degrees.
 16. An apparatus as in claim 1, further comprising:wherein the helix vane angle of incidence is within the range 15 degreesto 45 degrees.
 17. An apparatus as in claim 1, further comprising:wherein the elbow bend angle is within the range 10 degrees to 175degrees.
 18. An apparatus as in claim 1, further comprising: wherein thenominal inner wall diameter of helix elbow fitting outlet connectionportion is less than the nominal inner wall diameter of the helix elbowfitting inlet connection portion.
 19. A helix straight pipe fitting fora piping system having a nominal upstream pipe interior diameter and anominal downstream pipe inner diameter, the helix straight pipe fittingcomprising: an inlet, including an inlet connection portion, and anopposed outlet, including an outlet connection portion; a helix portionextending from a helix portion inlet having a first expandedcross-section relative to the nominal upstream pipe cross-section to ahelix portion outlet having a second expanded cross-section relative tothe nominal downstream pipe cross-section, the expanded cross-sectionssymmetrical and concentric with the respective upstream and downstreamnominal pipe cross-sections, the helix portion further including aplurality of helix vanes disposed equidistantly around the circumferenceof the helix portion and extending along the length of the helixportion, each of the helix vanes extending from a helix vane first endproximate the helix portion inlet to a helix vane second end proximatethe helix portion outlet, and oriented at an angle of incidence to theincoming fluid or media, wherein the helix vane first end is upstream ofthe helix vane second end; an expander extending from the inletconnection portion to the helix portion inlet; and, a reducer extendingfrom the helix portion outlet to the outlet connection portion; wherein,the helix portion imparts rotation on a bulk fluid, slurry or granularsystem flowing through it to improve laminar flow characteristics. 20.The apparatus of claim 19, further comprising: wherein the helix portionsecond cross-section is smaller than the helix portion firstcross-section, and the helix portion includes a continuous taper fromthe helix portion first cross-section to the helix portion secondcross-section.
 21. The apparatus of claim 20, further comprising:wherein the downstream nominal pipe diameter is less than the upstreamnominal pipe diameter.
 22. The apparatus of claim 19, furthercomprising: wherein the angle of incidence of each of the helix vanescreates a pitch of at least 1.0, such that each helix vane circumscribesthe helix portion inner wall at least once over the length of the helixportion.
 23. The apparatus of claim 19, further comprising: wherein theplurality of helix vanes includes at least three helix vanes.
 24. Theapparatus of claim 19, further comprising: wherein each helix vaneprojects past the nominal pipe inner wall circumference into the fluidflow.
 25. The apparatus of claim 19, further comprising: wherein thepiping system is designed for an anticipated range of nominal fluid flowconditions in the piping system, the nominal fluid flow conditionsincluding an anticipated range of outer laminar boundary layer thicknessin the fluid flowing through the piping system proximate the nominalpipe wall; and, wherein each helix vane projects into the fluid flow atleast as far as the maximum of the anticipated range of the outerlaminar boundary layer of the fluid stream in the nominal pipe inlet.26. The apparatus of claim 19, further comprising: wherein each helixvane projects past the nominal pipe inner wall circumference into thefluid flow by an amount at least 10 percent of the nominal pipe innerdiameter.
 27. The apparatus of claim 19, further comprising: whereineach helix vane projects past the nominal pipe inner wall circumferenceinto the fluid flow by an amount at least 10 percent of the first helixportion expanded cross-section diameter.
 28. A discharge flow amplifier,comprising: a canister extending from an inlet end to an outlet end, thecanister including an continuous open-ended conical cavity extendingfrom proximate the canister inlet end to the canister outlet end and thecavity perimeter enclosed by a tapered interior wall, the canisterincluding a coupling proximate the canister outlet end to connectselected discharge fittings; a helix portion disposed within thecanister conical cavity, the helix portion extending from a helixportion inlet proximate the canister inlet end to a helix portion outletand having a helix portion inside wall having a taper matching thecanister tapered interior wall, the distance between the helix portionoutlet and the canister outlet end defining a discharge mixing chamber,the helix portion further including a plurality of helix vanes; each ofthe helix vanes extending from a first end proximate the helix portioninlet to a second end proximate the helix portion outlet and projectinginward from the helix portion inside wall to a respective helix vaneedge, each of the helix vanes oriented at an angle of incidence toincoming fluid flow, and each helix vane oriented at an angle of attackto the incoming fluid flow; and, an end cap sealingly couplable to thecanister proximate the canister inlet end, the end cap including aninlet coupling adapted to connect to a source of flow; wherein, thehelix portion imparts rotation on a bulk fluid, slurry or granularsystem flowing through it to improve laminar flow characteristics. 29.The apparatus of claim 28, further comprising: wherein the helix portionis removable.
 30. The apparatus of claims 28 or 29, further comprising:wherein the plurality of helix vanes includes at least three helixvanes.
 31. The apparatus of claim 28 or 29, further comprising: whereinthe plurality of helix vanes consists of three helix vanes and each ofthe helix vane angles of incidence are selected so that each helix vanecircumscribes 180-degrees of the helix portion interior wall.
 32. Theapparatus of claims 28 or 29, further comprising: wherein each of theplurality of helix vanes has an angle of attack of less than 90-degrees.33. The apparatus of claims 28 or 29, further comprising: wherein theinlet coupling and discharge coupling are selected to mate with standardfirehose and nozzle fittings.
 34. The apparatus of claims 28 or 29,further comprising: wherein the canister interior tapered wall, thehelix portion interior wall, and the plurality of helix vanes aretapered at an angle in the range of approximately 2-degrees toapproximately 8-degrees.
 35. The apparatus of claim 29, furthercomprising: wherein the removable helix portion exterior wall is taperedto match the canister tapered interior wall.
 36. The apparatus of claims28 or 29, further comprising: wherein each of the plurality of helixvanes further includes a first corner proximate the respective helixvane first end and a second corner proximate the respective helix vanesecond end, and each of the respective first and second corners has aradius of approximately 1.0 inch (25.4 mm).
 37. The apparatus of claim29, further comprising: wherein the canister material is selected fromthe group consisting of brass, aluminum, and aluminum brass; and furtherwherein the removable helix portion is made from a polymer materialselected to substantially match the thermal expansion and contractioncharacteristics of the selected canister material within the anticipatedoperating environment temperature range.